Crushing mill



Aug.7,1956 G. RHWALD mL i 2,757,872

' CRUSHING MILL Filed Jan. 14, 1953 v2 Sheets-Sheet l l 25 r/ Il* i AVIII' INVENToRs GERHARD REHWALD 2| BY HEINRICH MEHLBEER /M uw ATTORNEYAug. 7, 1956 Filed Jan. 14, 1953 G. REHWALD ET AL CRUSHING MILL 2Sheets-Sheet 2 INVENToRs GERHARD REHWALD BY H lNRlCH MEHLBEER -l Q. uw

ATTORNEY United States Patent O "ice CRUSHING MILL Gerhard Rehwald,Aachen, and Heinrich Mehlbeer, Gey Uber Duren, Germany, assignors toStolherger Zink Aktiengesellschaft fr Bergbau und Huttenbetrieb, Aachen,Germany, a firm Application January 14, 1953, Serial No. 331,131

Claims priority, application Germany January 15, 1952 11 Claims. (Cl.241-275) This invention relates to a crushing mill, particularly of thecentrifugal type in which crushing pins are mounted in a carrier plateor head adapted to rotate on a vertical shaft. Mills of this kind areoften employed for the disintegration of soft and medium-hard materialsin piece form and on account of their particular mode of operation, areparticularly well suited for the selective crushing of such materials.

It was not possible, hitherto, to use these centrifugal pin typecrushing mills for finely disintegrating hard materials, or forselectively crushing mixtures or conglomerates containing highlyabrasive ingredients which may be harder than the material of whichparts of the mill effecting the crushing are made. The reason for thislimitation may be found in the fact, that heretofore no crushing mill ofthe aforesaid centrifugal type has been known which, under fullutilization of its capacity, would satisfy the following demands:

(a) Limitation of wear to the working parts of the mill.

(b) Simple exchange of all parts which are subject to wear, particularlyof the parts effecting disintegration.

(c) Complete utilization of the wearing parts.

(d) Adaption of the crushing forces to the degree of disintegration ofthe product.

(e) Easy repair of the entire working assembly.

() Minimum of dust.

(g) Disintegration by beating and impact without squeezing.

In view of the conventional centrifugal mills failing in most of theserespects, the invention has for its main object the provision of acentrifugal pin type crushing mill in which most of the aforesaiddemands will be complied with and which, therefore, will not besubjected to the disadvantages of the hitherto known machines of thiskind. In fact, a mill in accordance with this invention is distinctlydifferent from the known millsof this character as to represent anentirely new type for which the term impact mill seems appropriate. t

Another object of the invention resides in the provision of a mill inwhich means are provided for the propulsion of the material bylcentrifugal force against shock-producing as well as internal andexternal impact means, said means being preferably concentricallyarranged in a manner which greatly facilitates the selective action ofthe crushing mill.

A. further object of the invention resides in the formation of theactual working parts of the crushing mill of mutually independent partseasy of disassembly and ex- A change.

` impact which have been found to convey the best disintegrating effectsto `the material.

2,757,872 Patented Aug. 7, 1956 With these and other objects in view theinvention broadly resides in the provision of a pin type crushing ordisintegrating mill in which a distributing disc or plate is provided tobe supplied from above with the material to be treated, and in whichconcentrically within the ring of crushing pins, and outside thereof,impact surfaces are arranged in a certain mutual relation. Thearrangement, in accordance with additional features of the invention, ispreferably such that either the distributing plate forms a separatelydriven element independent of the rotary carrier supporting the crushingpins, or the distributing plate may be constructed to form part of thesaid crushing pin carrier itself.

Other objects and improvements of the invention may be gathered from thefollowing description of the accompanying drawing, in which severalembodiments of the new crushing mill are diagrammatically illustrated byway of example.

In the drawings:

Fig. l is an elevational sectional view of a crushing mill according tothe invention.

Fig. 2 is a similar sectional View showing a modification of the mill.

Fig. 3 is a fragmentary view showing a modification of the mounting ofthe crushing pins in the mill of Fig. 1.

Fig. 4 is a fragmetary isometric view partly in section showing amodication of the feed hopper of Fig. l, and

Fig. 5 is a sectional elevational view of still another modification ofthe crushing mill.

In the embodiment of the invention as shown in Figs. l and 2 acentrifugal plate or distributing disc 1 and a rotary carrier 2 areshown as separate, independent parts disposed in a housing 18 includinga disintegrating chamber. The centrifugal plate 1 is fastened to the topend of a rotary vertical shaft 3 and secured thereto by a closing cap 4which is xed to the shaft by means of a bolt 5. The drill hole 6 in thecap above the head of the bolt 5 may be filled by means of pitch, resin,or other suitable material.

The upper surface of the centrifugal plate 1 is covered by a layer ofwear resisting material attached thereupon in any suitable manner. Thislayer may be a flat layer 7 as is shown in Fig. 1 or a dished layer '7'as is shown in Fig. 2. The dished formation has the advantage ofcompensating due to its thickened circumference the increased wearexperienced by the outer portions of the plate and to impart to thematerial to be disintegrated a slightly upwardly inclined centrifugalforce while being thrown outwardly. `The carrier 2 is provided aroundits outer circumference with a plurality of pockets or bores for thereception of crushing pins 8. The pins 8 need not be fixed in the boresbut may be loosely inserted as is indicated at 3i) as they are held inposition by the centrifugal force acting upon them. It is preferable toprovide on the upper surface of the carrier 2 a ring 9 of wear resistingmaterial similar to the layer 7 or 7', which may consist of one or moreparts and through which the crushing pins 8 protrude into the spaceabove. The bores through ring 9 for pins 8 preferably provide a closerlit for the pins than the bores in the carrier 2. In this way thewearing ring 9 remains clamped in position without the necessity ofbeing separately fastened to the carrier. lf desired, the pockets orbores for the reception of the pins 8 may be made of different depth,which will make it possible, to remove partly worn pins from the deeperpockets and to insert them into the pockets of lesser depth toreplacethe more strongly worn pins at these places. Fig. 3 shows bores30 and 31 respectively of different depth. This figure also shows thatthe axes of the bores may be slanted. It is also advisable to providethe pockets or bores for the pins 8 with bottom openings 10 throughwhich a chaser or the like may be driven for forcing seized pins out oftheir pockets. If desired the bottom openings may be screw threaded sothat by driving a screw bolt ltherethrough, as is shown in Fig. 2, thepins may be forced out of their holes in carrier 2 and ring 9. Anotherway of removing worn pins is by the provision of slots 12 crossing thesaid pockets or bores. Byl driving wedges into these slots below thepins 8 the pins will be freed and may then be pulled out more easily.

In the embodiment shown in Figs. l and 2 the carrier 2 is designed toform the bearing for the shaft 3 of the centrifugal plate 1, whereby theshaft 3 may be driven over a pulley 14, and the carrier 2 over a pulley15 in the same or opposite rotational direction and at the same orvarying speeds. The carrier 2 is journaled in a sleeve or bushing 16which is supported on ribs 17 in housing l of the machine. A lateralopening 1.9 in the said housing serves for the passage of the drivingbelts for both, the Shaft 3 and the carrier 2. rThe belts (not shown)and pulley 14, are encased in a chamber 29 within the hopper-like lowerpart 21 of the housing and thus protected against damage by tredisintegrated material passing through hopper 21. Between the bushing 16and the lower surface of the carrier 2 a labyrinth packing 22 or othertightening means may be provided.

At its top the housing 13 has a wide opening which is closed by a lid23. An opening in the lid serves for the passage of a feed means in formof a chute or coaxial with the shaft 2. The hopper may also be arrangedat a slant so that at the moment of introduction of the material,suitably in the rotary sense of the centrifugal plate or disc 1, thematerial will already have a certain velocity. Such initial velocitytends to reduce the wear on the upper surface of the plate. Fig. 4 showsa hopper 24 which feeds the material spirally and eccentrically upondistributing disc or plate 1. A sleeve or ring 25 is provided to dependfrom the lid 23 into the disintegrating chamber of the mill. The outersurface of the sleeve serves as the inner impact surface 26 for thedisintegration of the material. For the purpose of adjusting the actionof the impact sleeve or ring 25, the ring may be adjustable in relationto thc plate 1, but the distance of the lower edge of the ring from theface of the plate 1 should be not smaller than the largest pieces oftheproduct. As indicated in Fig. 1, the ring 2S may be slightly inclinedinwardly, which will facilitate the entrance of the pieces as they areprecipitated by the action of the pins 8.

Outside the circle of crushing pins 2 an outer impact sleeve or ring 27is provided. This ring is clamped in position by the lid 23 and alsodepends into the disintegrating chamber of the mill. The inner side 2Sof the ring serves as the outer impact surface for the disintegration ofthe material propelled by the pins 8 against the said surface.

The part of the housing 18 which constitutes the disintegrating chamberand which is positioned in the zone of the impact action, is of annularcross section and of such diameter, that the outer impact ring 27depends freely into the said disintegration space, whereby a cycloneaction of the device is obtained.

The crushing mill in accordance with this intention operates as follows:

The pieces of material to be treated are introduced into the millthrough the hopper 24 which will feed it onto the rotating distributingdisc or plate 1. The centrifugal force propels the material outwardly infree flight against the crushing pins 8, whereby some pieces of thematerial becomes disintegrated by impact action.

Other pieces of the material are bandied by the pins 2 against the innerimpact surfaces 26, from which they fall back onto the plate 1 in orderagain to be thrown outwardly.

carrier 2 into the lower part of housing 18 and thence out of 'themachine by the bottom opening thereof.

In the illustrated embodiments of the invention wear occurs particularlyat the following parts or places:

1) On the upper surface of the distribution plate 1 by the friction orabrasion caused by the material,

(2) On the inner and outer impact surfaces due to impact,

(3) On the crushing pins E owing to impact and shock.

A moderate wear also occurs on the pin carrier 2 and also on thc uppersurface of the ring 9 due to the collection of material in front of thecrushing pins. The wear at these areas is relatively small for thereason of the upper external edge of the plate 1 or its protective layer7 being sutiiciently high above the surface of the carrier 2, so thatthe material impinges upon the crushing pins only at a certain distanceabove the ring 9. A further reduction in the wear on the mentioned partsis effected by employing the dished configuration of the layer 7 asshown in Fig. 2. As a result, the direction of propulsion of the piecesof the material is not horizontal, but slightly upwardly inclined.

The convenience with which worn parts may be exchanged is apparent fromthe foregoing specification. Regarding the exchange itself the followingconsiderations may be noted: As is known in the art, the specilic wearper unit weight of the material of the parts to each ton of the materialtreated is comparatively very low. This condition, however, could notfully be taken into account in conventional devices, as only a smallpercentage of the material of the parts exposed to wear could beutilized. A practically full utilization is now attained in thefollowing manner:

The protective layer 7 or 7 on the distributing plate 1 can bedimensioned so that its thickness will be proportional to the wear. Thecrushing pins are subjected only to wear on their upper freely exposedparts. By changing them from deep pockets 30 into more shallow pockets31 their useful life can be prolonged. The remaining pin stubs can bejoined by butt-welding to new pins of original length. The welding seamsof such repaired pins are preferably placed so that they are positionedin the zone of wear in order to leave the unworn ends for the nextwelding. The protective ring 9 of the pin carrier 2 can be removed afterremoval of the pins and reversed, or exchanged if necessary. Thediameters of this ring 9 and of the protective layer 7 can be chosen sothat both parts can be cut without waste from one plate.

Itwill be noted that in the construction of this new impact mill anyadditional wearing or wear causing parts, such as screw and rivet headsand the likeI are entirely or almost entirely absent at least in thedisintegrating zone of the device.

Instead of constructing the distributing disc or plate 1 and the rotarycarrier 2 as separate and independently driven parts, the said plate maybe integral with the said carrier. This simplifies the construction inso far as the shaft 3 and its driving means are then not required. Both,the distributing plate and the crushing pins Would rotate in the samesense and at the same speed, but for certain disintegrations sucharrangement is quite workable and useful. Fig. 5 shows such anarrangement. According to this ligure, rotary carrier 2 and distributingdisc are structurally united to form a distributing carrier 2 driven bypulley 15. The operation of this exemplification of the invention isobvious from the previous description.

It is to be understood that the invention is not intended to be limitedto the embodiment which has been described and illustrated, but that anydeviations to suit convenience or requirements may be made within thescope and meaning of the now following claims.

What we claim is:

1. A mill for disintegrating solid material in piece form comprising ahousing including a disintegrating chamber and a discharge chutecommunicating with said chamber, a vertical rotary shaft within thehousing, a distributing disc within said chamber tixedly seated upon theshaft, feed means for feeding pieces of the material to be disintegratedupon said disc for distribution by centirfugal force upon rotation ofsaid shaft and disc, a rotary carrier disposed coaxially with saidshaft, drive means for rotating said carrier, a plurality of crushingpins supported by said carrier in a ring arrangement radially spacedapart from the circumference of said disc, an inner impact sleevedisposed within said chamber above said disc coaxially therewith andhaving a diameter intermediate to the diameter of the pin ring and therotational axis of the shaft, the lower edge of said sleeve beingsituated above the throw-ofr` zone of the disc and an outer impactsleeve disposed within said chamber above said disc encompassing thedisc and the inner sleeve and having a diameter larger than the diameterof the pin ring, the said outer sleeve depending below the throw-olfzone of the disc, the said pins protruding above the disc and into theannular space defined between said sleeves whereby the centrifugallythrown-off pieces strike in free flight first said pins for crushingthereby and then said sleeves for disintegration by the impacttherewith, the material being finally dischargedA in disintegrated formthrough said chute.

2. A mill according to claim l, wherein a cover forms a top wall of saidhousing, the said impact sleeves depending from said cover into saidchamber and wherein the said feed means comprise a hopper extendingthrough said cover into the chamber.

3. A mill according to claim 1, wherein the said radial spacing betweenthe pin ring and the circumference of the disc is larger than themaximum size of the pieces to be disintegrated for effecting a freeflight'of all the pieces before striking the crushing pins.

4. A mill according to claim 1, wherein the upper level of the disc issituated above the upper level of said pin carrier.

5. A mill according to claim 1, wherein the material receiving side ofsaid disc is upwardly slanted in radial direction for lifting in thethrow-off zone of the disc toward said outer impact zone.

6. A mill according to claim 1, wherein the said feed means are slantedrelative to the plane of said disc for feeding material thereupon intangential direction.

7. A mill according to claim 1, wherein the said carrier is formed withcircumferentially spaced axial bores, the said pins being inserted insaid bores with a loose t and held therein by centrifugal force.

8. A mill according to claim 7, wherein a ring of wear resistantmaterial is fitted upon said carrier, the said ring being formed withcircumferentially spaced axial bores therethrough for passage of saidpins, the said pins tting the ring bores with a tight t for securing therings to the pins.

9. A millaccording to claim l, wherein the said carrier is formed withcircumferentially spaced axial bores of different depth, the said pinsbeing inserted in said bores with a loose lit and held therein bycentrifugal force` 10. A mill according to claim 1, wherein the saidcarrier is formed with circumferentially spaced bores slanted relativeto the axis of said shaft, the said pins being nserted in said boreswith a loose tit and held therein by centrifugal force.

1l. In a mill for disintegratng solid material in piece form, incombination, a rotary horizontally disposed distributing disc, feedmeans for feeding material to be disintegrated upon said disc fordistribution by centrifugal force upon rotation of said disc, a rotarycarrier disposed coaxially with said disc, drive means for rotating saiddisc and said carrier, a plurality of crushing pins extending from saidcarrier in a ring arrangement radially spaced apart from thecircumference of said disc, an inner substantially circular impactmember disposed above said disc coaXially therewith and having a radiussomewhat less than the radius of the pin ring, the said inner impactmember ending above the throw-oil' zone of said disc, and an outersubstantially circular impact member disposed above said discencompassing the pin ring and the disc and having a radius larger thanthe radius of the pin ring, the said outer impact member depending belowthe throw-oli zone of said disc, the said pins protruding into theannular space defined between said circular impact members whereby thecentrifugally thrown-off pieces strike in free flight first said pinsfor crushing thereby and then said impact members for disintegration bythe impact therewith.

References Cited in the tile of this patent UNITED STATES PATENTS1,641,445 London Sept. 6, 1927 2,009,957 Esch July 30, 1935 2,207,194Gruenaler July 9, 1940 FOREIGN PATENTS 14,003 Great Britain June 15,1909 30,346 Great Britain June 30, 1911 448,011 Germany Aug. 6, 1927553,055 Germany lune 21, 1932 656,996 Great Britain Sept. 5, 1951850,356 France Sept. l1, 1939 OTHER REFERENCES Serial No. 355,937, Nyiri(A. P. C.), published May 4, 1943.

